| 1. |
|
|
| 2. |
- Abbasi, R., et al.
(författare)
-
The IceCube data acquisition system : Signal capture, digitization, and timestamping
- 2009
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 601:3, s. 294-316
-
Tidskriftsartikel (refereegranskat)abstract
- IceCube is a km-scale neutrino observatory under construction at the South Pole with sensors both in the deep ice (InIce) and on the surface (IceTop). The sensors, called Digital Optical Modules (DOMs). detect, digitize and timestamp the signals from optical Cherenkov-radiation photons. The DOM Main Board (MB) data acquisition subsystem is connected to the central DAQ in the IceCube Laboratory (ICL) by a single twisted copper wire-pair and transmits packetized data on demand. Time calibration is maintained throughout the array by regular transmission to the DOMs of precisely timed analog signals, synchronized to a central GPS-disciplined clock. The design goals and consequent features, functional capabilities, and initial performance of the DOM MB, and the operation of a combined array of DOMs as a system, are described here. Experience with the first InIce strings and the IceTop stations indicates that the system design and performance goals have been achieved. (c) 2009 Elsevier B.V. All rights reserved.
|
|
| 3. |
- Abbasi, R., et al.
(författare)
-
Search for point sources of high energy neutrinos with final data from AMANDA-II
- 2009
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 79, s. 062001-
-
Tidskriftsartikel (refereegranskat)abstract
- We present a search for point sources of high energy neutrinos using 3.8 yr of data recorded by AMANDA-II during 2000-2006. After reconstructing muon tracks and applying selection criteria designed to optimally retain neutrino-induced events originating in the northern sky, we arrive at a sample of 6595 candidate events, predominantly from atmospheric neutrinos with primary energy 100 GeV to 8 TeV. Our search of this sample reveals no indications of a neutrino point source. We place the most stringent limits to date on E(-2) neutrino fluxes from points in the northern sky, with an average upper limit of E(2)Phi(nu mu)+nu(tau)<= 5.2x10(-11) TeV cm(-2) s(-1) on the sum of nu(mu) and nu(tau) fluxes, assumed equal, over the energy range from 1.9 TeV to 2.5 PeV.
|
|
| 4. |
- Abbasi, R., et al.
(författare)
-
Solar energetic particle spectrum on 2006 December 13 determined by IceTop
- 2008
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 689:1, s. L65-L68
-
Tidskriftsartikel (refereegranskat)abstract
- On 2006 December 13 the IceTop air shower array at the South Pole detected a major solar particle event. By numerically simulating the response of the IceTop tanks, which are thick Cerenkov detectors with multiple thresholds deployed at high altitude with no geomagnetic cutoff, we determined the particle energy spectrum in the energy range 0.6-7.6 GeV. This is the first such spectral measurement using a single instrument with a well-defined viewing direction. We compare the IceTop spectrum and its time evolution with previously published results and outline plans for improved resolution of future solar particle spectra.
|
|
| 5. |
- Achterberg, A., et al.
(författare)
-
The search for muon neutrinos from northern hemisphere gamma-ray bursts with AMANDA
- 2008
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 674:1, s. 357-370
-
Tidskriftsartikel (refereegranskat)abstract
- We present the results of the analysis of neutrino observations by the Antarctic Muon and Neutrino Detector Array (AMANDA) correlated with photon observations of more than 400 gamma-ray bursts (GRBs) in the northern hemisphere from 1997 to 2003. During this time period, AMANDA's effective collection area for muon neutrinos was larger than that of any other existing detector. After the application of various selection criteria to our data, we expect similar to 1 neutrino event and <2 background events. Based on our observations of zero events during and immediately prior to the GRBs in the data set, we set the most stringent upper limit on muon neutrino emission correlated with GRBs. Assuming a Waxman-Bahcall spectrum and incorporating all systematic uncertainties, our flux upper limit has a normalization at 1 PeV of E-2 Phi(nu) <= 6.3 x 10(-9) GeV cm(-2) s(-1) sr(-1), with 90% of the events expected within the energy range of similar to 10 TeV to similar to 3 PeV. The impact of this limit on several theoretical models of GRBs is discussed, as well as the future potential for detection of GRBs by next-generation neutrino telescopes. Finally, we briefly describe several modifications to this analysis in order to apply it to other types of transient point sources.
|
|
| 6. |
- Abbasi, R., et al.
(författare)
-
SEARCH FOR HIGH-ENERGY MUON NEUTRINOS FROM THE "NAKED-EYE" GRB 080319B WITH THE IceCube NEUTRINO TELESCOPE
- 2009
-
Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 701:2, s. 1721-1731
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a search with the IceCube detector for high-energy muon neutrinos from GRB 080319B, one of the brightest gamma-ray bursts (GRBs) ever observed. The fireball model predicts that a mean of 0.1 events should be detected by IceCube for a bulk Lorentz boost of the jet of 300. In both the direct on-time window of 66 s and an extended window of about 300 s around the GRB, no excess was found above background. The 90% CL upper limit on the number of track-like events from the GRB is 2.7, corresponding to a muon neutrino fluence limit of 9.5 x 10(-3) erg cm(-2) in the energy range between 120 TeV and 2.2 PeV, which contains 90% of the expected events.
|
|
| 7. |
- Achterberg, A., et al.
(författare)
-
Detection of atmospheric muon neutrinos with the IceCube 9-string detector
- 2007
-
Ingår i: Physical Review D - Particles, Fields, Gravitation and Cosmology. - 1550-7998. ; 76:2, s. 027101-
-
Tidskriftsartikel (refereegranskat)abstract
- The IceCube neutrino detector is a cubic kilometer TeV to PeV neutrino detector under construction at the geographic South Pole. The dominant population of neutrinos detected in IceCube is due to meson decay in cosmic-ray air showers. These atmospheric neutrinos are relatively well understood and serve as a calibration and verification tool for the new detector. In 2006, the detector was approximately 10% completed, and we report on data acquired from the detector in this configuration. We observe an atmospheric neutrino signal consistent with expectations, demonstrating that the IceCube detector is capable of identifying neutrino events. In the first 137.4 days of live time, 234 neutrino candidates were selected with an expectation of 211 +/- 76.1(syst)+/- 14.5(stat) events from atmospheric neutrinos.
|
|
| 8. |
|
|
| 9. |
- Achterberg, A., et al.
(författare)
-
Multiyear search for a diffuse flux of muon neutrinos with AMANDA-II
- 2007
-
Ingår i: Physical Review D - Particles, Fields, Gravitation and Cosmology. - 1550-7998. ; 76:4, s. 042008-
-
Tidskriftsartikel (refereegranskat)abstract
- A search for TeV-PeV muon neutrinos from unresolved sources was performed on AMANDA-II data collected between 2000 and 2003 with an equivalent live time of 807 days. This diffuse analysis sought to find an extraterrestrial neutrino flux from sources with nonthermal components. The signal is expected to have a harder spectrum than the atmospheric muon and neutrino backgrounds. Since no excess of events was seen in the data over the expected background, an upper limit of E-2 Phi(90%C.L.)< 7.4x10(-8) GeV cm(-2) s(-1) sr(-1) is placed on the diffuse flux of muon neutrinos with a Phi proportional to E-2 spectrum in the energy range 16 TeV to 2.5 PeV. This is currently the most sensitive Phi proportional to E-2 diffuse astrophysical neutrino limit. We also set upper limits for astrophysical and prompt neutrino models, all of which have spectra different from Phi proportional to E-2.
|
|
| 10. |
- Ackermann, M., et al.
(författare)
-
Search for ultra-high-energy neutrinos with amanda-II
- 2008
-
Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 675:2, s. 1014-1024
-
Tidskriftsartikel (refereegranskat)abstract
- A search for diffuse neutrinos with energies in excess of 10(5) GeV is conducted with AMANDA-II data recorded between 2000 and 2002. Above 10(7) GeV, the Earth is essentially opaque to neutrinos. This fact, combined with the limited overburden of the AMANDA-II detector ( roughly 1.5 km), concentrates these ultra-high-energy neutrinos at the horizon. The primary background for this analysis is bundles of downgoing, high-energy muons from the interaction of cosmic rays in the atmosphere. No statistically significant excess above the expected background is seen in the data, and an upper limit is set on the diffuse all-flavor neutrino flux of E-2 Phi(90%CL) < 2.7x10(-7) GeV cm(-2) s(-1) sr(-1) valid over the energy range of 2x10(5) to 10(9) GeV. A number of models that predict neutrino fluxes from active galactic nuclei are excluded at the 90% confidence level.
|
|
| 11. |
- Abbasi, R, et al.
(författare)
-
Extending the Search for Neutrino Point Sources with IceCube above the Horizon
- 2009
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:22, s. 221102-
-
Tidskriftsartikel (refereegranskat)abstract
- Point source searches with the IceCube neutrino telescope have been restricted to one hemisphere, due to the exclusive selection of upward going events as a way of rejecting the atmospheric muon background. We show that the region above the horizon can be included by suppressing the background through energy-sensitive cuts. This improves the sensitivity above PeV energies, previously not accessible for declinations of more than a few degrees below the horizon due to the absorption of neutrinos in Earth. We present results based on data collected with 22 strings of IceCube, extending its field of view and energy reach for point source searches. No significant excess above the atmospheric background is observed in a sky scan and in tests of source candidates. Upper limits are reported, which for the first time cover point sources in the southern sky up to EeV energies.
|
|
| 12. |
- Abbasi, R, et al.
(författare)
-
FIRST NEUTRINO POINT-SOURCE RESULTS FROM THE 22 STRING ICECUBE DETECTOR
- 2009
-
Ingår i: Astrophysical Journal Letters. - 2041-8205. ; 701, s. L47-L51
-
Tidskriftsartikel (refereegranskat)abstract
- We present new results of searches for neutrino point sources in the northern sky, using data recorded in 2007-2008 with 22 strings of the IceCube detector (approximately one-fourth of the planned total) and 275.7 days of live time. The final sample of 5114 neutrino candidate events agrees well with the expected background of atmospheric muon neutrinos and a small component of atmospheric muons. No evidence of a point source is found, with the most significant excess of events in the sky at 2.2 sigma after accounting for all trials. The average upper limit over the northern sky for point sources of muon-neutrinos with E-2 spectrum is E-2 Phi(v mu) < 1.4 x 10(-11) TeV cm(-2) s(-1), in the energy range from 3 TeV to 3 PeV, improving the previous best average upper limit by the AMANDA-II detector by a factor of 2.
|
|
| 13. |
- Abbasi, R, et al.
(författare)
-
Limits on a Muon Flux from Neutralino Annihilations in the Sun with the IceCube 22-String Detector
- 2009
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:20, s. 201302-
-
Tidskriftsartikel (refereegranskat)abstract
- A search for muon neutrinos from neutralino annihilations in the Sun has been performed with the IceCube 22-string neutrino detector using data collected in 104.3 days of live time in 2007. No excess over the expected atmospheric background has been observed. Upper limits have been obtained on the annihilation rate of captured neutralinos in the Sun and converted to limits on the weakly interacting massive particle (WIMP) proton cross sections for WIMP masses in the range 250-5000 GeV. These results are the most stringent limits to date on neutralino annihilation in the Sun.
|
|
| 14. |
- Abbasi, R, et al.
(författare)
-
Determination of the atmospheric neutrino flux and searches for new physics with AMANDA-II
- 2009
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 79, s. 102005-
-
Tidskriftsartikel (refereegranskat)abstract
- The AMANDA-II detector, operating since 2000 in the deep ice at the geographic South Pole, has accumulated a large sample of atmospheric muon neutrinos in the 100 GeV to 10 TeV energy range. The zenith angle and energy distribution of these events can be used to search for various phenomenological signatures of quantum gravity in the neutrino sector, such as violation of Lorentz invariance or quantum decoherence. Analyzing a set of 5511 candidate neutrino events collected during 1387 days of livetime from 2000 to 2006, we find no evidence for such effects and set upper limits on violation of Lorentz invariance and quantum decoherence parameters using a maximum likelihood method. Given the absence of evidence for new flavor-changing physics, we use the same methodology to determine the conventional atmospheric muon neutrino flux above 100 GeV.
|
|
| 15. |
|
|
| 16. |
- Andersson, P., et al.
(författare)
-
Selective detection of C-13 by laser photodetachment mass spectrometry
- 2008
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 266:16, s. 3667-3673
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we demonstrate how laser photodetachment mass spectrometry (LPMS) can be used to selectively detect C-13(-) ions in the presence of C-12(-) ions in a low energy ion beam. An isotopically enriched beam of carbon ions consisting of equal amounts of C-13(-) and 12C- ions was extracted from an ion source. The ions interacted with a laser beam in a collinear geometry over a distance of 70 cm. Residual atoms produced in the photodetachment process were detected in a neutral particle detector placed downstream of the collinear interaction region. By making use of the Doppler effect we were able to selectively photodetach C-13(-) ions. The number of detected C-13 atoms was 13 times larger than the number of detected C-12 atoms. The population of the excited, weakly bound D-2 excited state of the C- ion was depleted by the use of a second laser. This significantly reduced the background accompanying the signal arising from the photodetachment of the S-4 ground state C- ion. Different applications of the LPMS method will be discussed in the paper.
|
|
| 17. |
- Persson, Magnus, et al.
(författare)
-
Solute transport dynamics by high-resolution dye tracer experiments - Image analysis and time moments
- 2005
-
Ingår i: Vadose Zone Journal. - : Wiley. - 1539-1663. ; 4:3, s. 856-865
-
Tidskriftsartikel (refereegranskat)abstract
- Accurate measurements of solute concentration are needed to conduct studies of solute transport process in unsaturated soil. In this paper we present a method of obtaining accurate measurements in and space using dye infiltration and image analysis. The soil color was related to the dye concentration in the soil (C-s) using 74 small calibration samples. The overall root mean square error (RMSE) 0.057 g dm(-3), however, for C-s < 0.75 g dm(-3), the RMSE was only 0.032 g dm(-3). Variability of the concentration estimates at the pixel scale could be reduced by using an average filter. We used the calibration relationship during four infiltration experiments in a 0.95 by 0.975 m large Plexiglas Hele-Shaw cell to calculate dye concentration patterns. Using the first and second order time moments, the dispersivity lambda was calculated for nine different artificial column widths, from 0.0014 (local-scale) to 0.72 m (meso-scale). The horizontally averaged lambda proved to be identical for column widths from 0.0014 to 0.045 m. For larger scales, lambda gradually increased. We noticed that the two experiments with higher flow (1 and 2) and the two experiments with lower flow (3 and 4) showed an almost identical variation of meso-scale lambda with depth. We concluded that above a specific critical value of theta (similar to 0.22 m(3) m(-3)), solute mixing is enhanced, leading to a lower lambda, and that solute transport can be described as a convective-dispersive process. When theta is lower than this critical level, part of the porosity is deactivated and mixing between individual stream tubes decreases, which implies that transport then occurs as a stochastic-convective process.
|
|
| 18. |
- Schwid, SR, et al.
(författare)
-
Enhanced benefit of increasing interferon beta-1a dose and frequency in relapsing multiple sclerosis - The EVIDENCE study
- 2005
-
Ingår i: Archives of Neurology. - 0003-9942. ; 62:5, s. 785-792
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The EVIDENCE (Evidence of Interferon Dose-Response: European North American Comparative Efficacy) Study demonstrated that patients with multiple sclerosis (MS) who initiate interferon beta-la therapy with 44 μ g 3 times weekly (TIW) were less likely to have a relapse or activity on magnetic resonance imaging (MRI) compared with those who initiate therapy at a dosage of 30 μ g 1 time weekly (QW). Objective: To determine the effect of changing the dosage from 30 μ g QW to 44 μ g TIW in this extension of the EVIDENCE StudyDesign/Patients: Patients with relapsing MS originally randomized to interferon beta-1a, 30 μ g QW, during the comparative phase of the study changed to 44 μ g TIW, whereas patients originally randomized to 44 μ g TIW continued that regimen. Patients were followed up, on average, for an additional 32 weeks. Main Outcome Measure: The within-patient pretransition to posttransition change in relapse rate. Results: At the transition visit, 223 (73%) of 306 patients receiving 30 μ g QW converted to 44 μ g TIW, and 272 (91%) of 299 receiving 44-μ g TIW continued the same therapy. The posttransition annualized relapse rate decreased from 0.64 to 0.32 for patients increasing the dose (P<.001) and from 0.46 to 0.34 for patients continuing 44-μ g TIW (P =.03). The change was greater in those increasing dose and frequency (P=.047). Patients converting to the 44-μ g,TIW regimen had fewer active lesions on T2-weighted MRI compared with-before the transition (P=.02), whereas those continuing the 44-μ g TIW regimen had no significant change in T2 active lesions. Patients who converted to high-dose/high-frequency interferon beta-la therapy had increased rates of adverse events and treatment terminations consistent with the initiation of high-dose subcutaneous interferon therapy. Conclusions: Patients receiving interferon beta-la improved on clinical and MRI disease measures when they changed from 30μ g QW to 44 μ g TIW.
|
|
| 19. |
|
|
| 20. |
|
|
| 21. |
- Mårtensson, Ulrika, et al.
(författare)
-
Deletion of the G protein-coupled receptor 30 impairs glucose tolerance, reduces bone growth, increases blood pressure, and eliminates estradiol-stimulated insulin release in female mice.
- 2009
-
Ingår i: Endocrinology. - : The Endocrine Society. - 1945-7170 .- 0013-7227. ; 150:2, s. 687-98
-
Tidskriftsartikel (refereegranskat)abstract
- In vitro studies suggest that the G protein-coupled receptor (GPR) 30 is a functional estrogen receptor. However, the physiological role of GPR30 in vivo is unknown, and it remains to be determined whether GPR30 is an estrogen receptor also in vivo. To this end, we studied the effects of disrupting the GPR30 gene in female and male mice. Female GPR30((-/-)) mice had hyperglycemia and impaired glucose tolerance, reduced body growth, increased blood pressure, and reduced serum IGF-I levels. The reduced growth correlated with a proportional decrease in skeletal development. The elevated blood pressure was associated with an increased vascular resistance manifested as an increased media to lumen ratio of the resistance arteries. The hyperglycemia and impaired glucose tolerance in vivo were associated with decreased insulin expression and release in vivo and in vitro in isolated pancreatic islets. GPR30 is expressed in islets, and GPR30 deletion abolished estradiol-stimulated insulin release both in vivo in ovariectomized adult mice and in vitro in isolated islets. Our findings show that GPR30 is important for several metabolic functions in female mice, including estradiol-stimulated insulin release.
|
|
| 22. |
- Olsson, Daniel, et al.
(författare)
-
cis-[2,6-bis(di-tert-butylphosphinomethyl)cyclohexyl-kappa P-3,C-1,P '] bromidopalladium(II)
- 2007
-
Ingår i: Acta Crystallographica Section E: Structure Reports Online. - 1600-5368. ; 63:7, s. 1630-1969
-
Tidskriftsartikel (refereegranskat)abstract
- The title compound, [PdBr(C24H49P2)], has a distorted square-planar coordination geometry with the P, C, P'-tridentate ligand forming two five-membered chelate rings. The Br atom is displaced from the square plane by 0.560 (6) angstrom.
|
|
| 23. |
- Schara, U, et al.
(författare)
-
Ephedrine therapy in eight patients with congenital myasthenic syndrome due to DOK7 mutations.
- 2009
-
Ingår i: Neuromuscular disorders : NMD. - : Elsevier BV. - 1873-2364 .- 0960-8966. ; 19:12, s. 828-32
-
Tidskriftsartikel (refereegranskat)abstract
- In congenital myasthenic syndrome with DOK7 mutations ephedrine was reported to be beneficial in single patients. We carried out a small, open and prospective cohort study in eight European patients manifesting from birth to 12 years. Five patients showed limb-girdle and facial weakness, three a floppy infant syndrome with bulbar symptoms and/or respiratory distress. Ephedrine was started with 25 mg/day and slowly increased to 75-100 mg/day. Within weeks after starting therapy an improvement was observed in all patients and clinical follow-up disclosed positive effects more pronounced on proximal muscle weakness and strength using MRC scale. Effects on facial weakness were less pronounced. Vital capacity measurements and repetitive stimulation tests did not improve in the same way as clinical symptoms did. These investigations are appropriate to confirm the diagnosis in case of pathological results, but they might not be appropriate means to monitor patients under ephedrine therapy.
|
|
| 24. |
|
|
| 25. |
- Yam-Puc, Alejandro, et al.
(författare)
-
Trinorsesquiterpenoids from the Root Extract of Pentalinon andrieuxii
- 2009
-
Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 72:4, s. 745-748
-
Tidskriftsartikel (refereegranskat)abstract
- Two unusual trinorsesquiterpenoids, urechitols A (1) and B (2), were isolated from the root extract of Pentalinon andrieuxii, a plant used commonly in Yucatecan traditional medicine to treat leishmaniasis. The structures of I and 2 were identified by interpretation of their spectroscopic data and chemical correlation reactions. The relative stereochemistry of I was confirmed through an X-ray crystallographic study.
|
|
